- Influence of uniaxial deformation on the transport mechanism behaviour in semicrystalline polymers

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Influence of uniaxial deformation on the transport mechanism behaviour in semicrystalline polymers

Permeation trough a polymer is the mass transport of low molecular liquids or gas molecules from one surface of a polymer to the opposite side. The process is controlled by diffusion and solubility of the molecules in the solid phase of the polymer. The investigation of these process is relevant for several applications like food packages or membranes in physical process like gas separation. The transport behavior of these films is influenced by mechanical load during application and leads to the optimization of film thickness in respect to the permeability and mechanical stiffness.

The developed device measures non-destructively the mass transport parameters of a polymer film depending on the mechanical load. The advantage of this apparatus is a sealing system, which allows the mobility of the film sample without any loss of the test-gas. Therefore the film is able to relax after an application of a defined load regime.

First of all the basic theory of the mass transport and deformation models of polymers is described. The combination of these accepted theory shows, how the transport and deformation processes influence each other. The impact of mechanical load on a polyolefin film leads to a change of the molecular structure and therefore the mobility of its molecules. This effect itself influences the mass transport behavior, which can be shown with this new measurement device. The change in molecular structure is confirmed by electronmicroscopical determination.